Guatemala launched a manhunt on Thursday after 18 indigenous Guatemalans were killed in a hit-and-run by a truck driver who fled the scene.
The Central American nation announced three days of mourning after the incident Wednesday night in the western town of Nahuala, whose population of around 65,000 are mostly K'iche' Maya.
A group of people had converged at the entrance of the town, at the scene of another hit-and-run in which a local community leader was killed, when they, in turn, were hit by a truck with its lights off on a road without street lighting.
Chilling images from the scene showed the victims' bodies in their brightly colored clothing laid out in a line on the asphalt, as relatives cried out in anguish.
"In total there are 18 deaths that have been counted in this tragedy," fire department spokesman Cecilio Chacaj told AFP, revising down a previous toll of 30 that he attributed to early chaos on the scene where bodies were piled up on top of another.
Three of the dead were children, Chacaj said.
Another 20 people were injured in the accident, several seriously, and were being treated in hospitals.
The government announced three days of mourning starting Thursday, while President Jimmy Morales tweeted his condolences.
"We are currently coordinating actions to provide all the support to the victims' families," he said.
Police spokesman Pablo Castillo told reporters that an operation was underway to track down the driver.
He added that investigators were initially prevented from getting to the scene by angry residents and relatives of the victims, but were given access after opening a dialogue with community leaders.
Local reports said the man killed in the first accident was a community leader and president of the state Council of Urban and Rural Development, though authorities have not confirmed this.
The semi-trailer did not have its lights on when it struck the group of people, which may have been why the driver did not spot them, while the highway was also unlit, according to local media.
Traffic rules are frequently ignored in Guatemala, a nation of some 16.5 million people.